Enhanced seismic performance of non-standard bolted flange joints for petrochemical piping systems

•Two non-standard seismically enhanced bolted flange joints were designed.•Performance of proposed joints was evaluated through bending and axial tests.•The joints showed favourable ductility, energy dissipation and leakage capacity.•Experimental leakage and yield loads of joints were above allowable design loads.•Joint capacities were far above seismic demands obtained from a Case Study.

This paper presents an experimental test campaign carried out on a number of seismically enhanced Bolted Flange Joints. In particular, two non-standard Bolted Flange Joints, comparatively thinner than standard ones, were designed and their performance was evaluated through several monotonic and cyclic tests. Experimental results exhibited a favourable performance of the examined joints under bending and axial loading and moderate internal pressure; a good capacity in terms of strength, ductility, energy dissipation and leakage was observed. A comparison between experimental results and Code-based design loads proved the usability of the proposed joints during and after Operating Basis Earthquake ground motions. Finally, a comparison between capacity and seismic demands of these joints adopted in a piping system of a realistic Case Study suggested their suitability for seismic applications as well as some building code deficiency with respect to response modification factors.